RATIONALE: Polyunsaturated fatty acids are important for normal growth and development. One type, called omega-3 fatty acids (found in fish, fish oil, and some other foods), may affect the growth of abnormal breast cells.

PURPOSE: This randomized pilot trial is studying how well omega-3 fatty acids work in treating women with newly diagnosed ductal carcinoma in situ and/or atypical ductal hyperplasia.

OBJECTIVES:

• To determine the effect of omega-3 fatty acids on markers of breast cancer progression in women with newly diagnosed ductal carcinoma in situ and/or atypical ductal hyperplasia.
• To determine the effect of omega-3 fatty acids on specific targets identified by microarray in breast cancer cells and in primary cultures from benign and malignant breast tissue biopsies.

OUTLINE: This is a multicenter study. Patients are randomized to 1 of 2 treatment arms.

• Arm I: Patients receive oral omega-3 fatty acid capsules 3 times daily for up to 8 weeks.
• Arm II: Patients receive oral placebo olive oil capsules 3 times daily for up to 8 weeks.

Patients complete questionnaires at baseline, weekly during study treatment, at the completion of study treatment, and then at 30 days after completion of study treatment. These questionnaires include the Fish Oil Adverse Event Questionnaire, the Diet and Family History Questionnaire, the Changes to Diet and Medications Questionnaire, and the Post-Intervention Questionnaire.

Patients undergo blood, urine, nipple aspirate, and tissue sample collection at baseline and after completion of study treatment for translational research studies. Blood samples are analyzed for genetic markers for breast cancer risk and progression by microarray analysis and red blood cell (RBC) fatty acids. Nipple aspirate samples are analyzed for fatty acids to determine the extent to which omega-3 fatty acid supplementation alters the fatty acid profile of breast tissue. Tissue samples are analyzed for the presence of ductal carcinoma in situ and/or atypical ductal hyperplasia or invasive cancer. Leftover blood, urine, nipple aspirate, and tissue samples are stored for future research studies.

After completion of study treatment, patients are followed at 30 days.

DISEASE CHARACTERISTICS:

• Biopsy confirmed diagnosis of any of the following:

  • Ductal carcinoma in situ (DCIS) and/or atypical ductal hyperplasia (ADH)
  • DCIS with a component of invasive carcinoma
  • ADH with a component of invasive carcinoma
  • DCIS and ADH with a component of invasive carcinoma

• Newly diagnosed disease

• No pure invasive breast cancer on biopsy without a component of DCIS or ADH

• Hormone receptor status not specified

PATIENT CHARACTERISTICS:

• Female
• Menopausal status not specified
• Not pregnant
• Negative pregnancy test
• Speaks English or Spanish
• No allergy to fish oil or olive oil
• No condition that, in the opinion of the study clinician, would make participation in the study harmful to the patient

PRIOR CONCURRENT THERAPY:

• No concurrent therapeutic anticoagulation
• No concurrent use of fish oil > 1 g/day